Oka-Kira Erika, Tateno Kumiko, Miura Kin-ichiro, Haga Tatsuya, Hayashi Masaki, Harada Kyuya, Sato Shusei, Tabata Satoshi, Shikazono Naoya, Tanaka Atsushi, Watanabe Yuichiro, Fukuhara Izumi, Nagata Toshiyuki, Kawaguchi Masayoshi
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Tokyo 113-0033, Japan.
Plant J. 2005 Nov;44(3):505-15. doi: 10.1111/j.1365-313X.2005.02543.x.
A novel hypernodulation mutant line was isolated from Lotus japonicus Miyakojima MG-20 by irradiation with a helium ion beam. This mutant, named klavier (klv), had roots that were densely covered with small nodules. The nodulation zone of klv was significantly wider than that of the wild type. Grafting experiments showed that klv is impaired in the long-distance shoot-to-root autoregulatory mechanism. Thus the shoot genotype was found to be responsible for the negative regulation of nodule development by KLV. Nodulation of klv showed a higher tolerance to nitrogen (KNO3) than the wild type, which is a common feature of hypernodulating mutants. In addition to an increased number of nodules, the klv mutant showed convex leaf veins on the adaxial leaf surface, markedly delayed flowering and dwarf phenotypes. Microscopic examination of the leaf veins revealed that they were discontinuous. Other phenotypes such as fasciated stems, increased number of flowers and bifurcated pistils were also frequently observed in the klv mutant. Among these phenotypes, hypernodulation, aberrant leaf vein formation and significantly delayed flowering were all linked in a monogenic and recessive manner, indicating that these phenotypes are caused by either a single mutation, or tightly linked mutations. KLV was mapped within 0.29 cM on the long arm of chromosome 1.
通过氦离子束辐照从日本百脉根宫古岛MG-20中分离出一个新型超结瘤突变株系。这个名为klavier（klv）的突变体根系上密集覆盖着小结节。klv的结瘤区明显比野生型宽。嫁接实验表明，klv在从地上部到根部的长距离自动调节机制中存在缺陷。因此，发现地上部基因型负责KLV对根瘤发育的负调控。klv的结瘤对氮（KNO3）的耐受性比野生型高，这是超结瘤突变体的一个共同特征。除了根瘤数量增加外，klv突变体在叶片近轴表面还表现出凸起的叶脉、明显延迟的开花和矮化表型。对叶脉的显微镜检查显示它们是不连续的。在klv突变体中还经常观察到其他表型，如茎扁化、花数量增加和雌蕊分叉。在这些表型中，超结瘤、异常叶脉形成和明显延迟的开花都以单基因隐性方式相关联，表明这些表型是由单个突变或紧密连锁的突变引起的。KLV被定位在第1号染色体长臂上0.29 cM范围内。
